Superoleophobic and conductive carbon nanofiber/fluoropolymer composite films
journal contributionposted on 2012-08-21, 00:00 authored by Arindam Das, Thomas M. Schutzius, Ilker S. Bayer, Constantine M. Megaridis
A solution-based, large-area coating procedure is developed to produce conductive polymer composite films consisting of hollow-core carbon nanofibers (CNFs) and a fluoroacrylic copolymer available as a water-based dispersion. CNFs (100 nm dia., length similar to 130 mu m) were dispersed by sonication in a formic acid/acetone co-solvent system, which enabled colloidal stability and direct blending of the CNFs and aqueous fluoroacrylic dispersions in the absence of surfactants. The dispersions were sprayed on smooth and microtextured surfaces, thus forming conformal coatings after drying. Nanostructured composite films of different degrees of oil and water repellency were fabricated by varying the concentration of CNFs. The effect of substrate texture and CNF content on oil/water repellency was studied. Water and oil static contact angles (CAs) ranged from 98 degrees to 164 degrees and from 61 degrees to 164 degrees, respectively. Some coatings with the highest water/oil CAs displayed self-cleaning behavior (droplet roll-off angles <10 degrees). Inherent conductivity of the composite films ranged from 63 to 940 S/m at CNF concentrations from 10 to 60 wt.%, respectively. Replacement of the long CNFs with shorter solid-core carbon nanowhiskers (150 nm dia., length 6-8 mu m) produced stable fluoropolymer-nanowhisker dispersions, which were ink-jetted to generate hydrophobic, conductive, printed line patterns with a feature size similar to 100 mu m. (C) 2011 Elsevier Ltd. All rights reserved.
We thank DuPont Inc. for providing the Capstone® ST-100 product and Applied Sciences Inc, for providing CNF samples of Pyrograf III; PR-24-XT-HHT. The authors acknowledge MicroFab Technologies for providing equipment and personnel for the ink-jetting experiments.
Publisher StatementNOTICE: this is the author’s version of a work that was accepted for publication in Carbon. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Carbon, [Vol 50, Issue 3, March 2012] DOI: 10.1016/j.carbon.2011.11.006